Autumn began in the Southern Hemisphere at 0:06 am (Brasília time) this Wednesday (20) and will last until June 21st. This year, the season will be marked by the weakening of the El Niño phenomenon and the record of temperatures above the historical average in all regions of the country.
The National Institute of Meteorology (Inmet) and the National Institute for Space Research (Inpe) predict that the months of April, May and June will be warmer compared to the average of recent years. The exception is for the center-south of Rio Grande do Sul, where temperatures are predicted to be within normal limits.
According to Inmet’s general coordinator, Márcia Seabra, in some areas, the temperature can be up to 1 or 2 degrees above average throughout the period. For the meteorologist, in addition to phenomena such as El Niño and La Niña, the temperature differences during this year’s autumn can be explained by global warming.
“It’s already very difficult today for us to say that it’s hotter because of El Niño. It is more plausible to say that the temperature is rising, yes, because of global warming and climate change. Because, regardless of [fenômeno] El Niño, temperatures are getting very high – that’s what we saw last year. This is probably something you have to adapt to: the fact that temperatures tend to get higher regardless of the El Niño or La Niña phenomena”, he explains.
The boy
The El Niño phenomenon, which peaked in December last year, has been weakening in recent months. “Probably by autumn we should already have this transition from El Niño to a more neutral condition”, explains the meteorologist.
During this phenomenon, the waters of the Pacific Ocean, close to the Equator, warm up. As a result, there are changes in the formation of rain, wind circulation and temperature.
At the end of autumn, it is possible that the La Niña phenomenon will begin to form in Brazil, gaining strength in the second half of the year. La Niña is characterized by the cooling of Pacific waters. “What happens is below average rainfall in the South Region and above average in the North and Northeast regions”, says Márcia Seabra.
Rains
Rainfall is expected to be below the historical average in autumn in most of the North, Northeast and Central-West regions, especially due to the impacts that El Niño may still cause. In areas north of Roraima, northwest and southwest of Amazonas and west of Acre, the forecast is for favorable conditions for rain close to or above average during the quarter.
In the South and Southeast regions, rains with values above the climatology are predicted, mainly in Rio Grande do Sul and Santa Catarina, in areas of São Paulo and southern Minas Gerais. In other areas of the Southeast, the trend is for rain close to and slightly below average.
Harvest
In the South Region, the expected rainfall volumes should maintain soil water levels at a satisfactory level for the phases of greatest water need for second-crop crops, but may harm first-crop harvesting operations.
In the Central-West and Southeast regions, the forecast of above-average rain in areas of Mato Grosso do Sul, São Paulo and southern Minas Gerais should favor the maintenance of water storage in the soil, benefiting second-crop crops. In other areas, there is the possibility of reducing soil moisture. According to Inmet, autumn should not see frosts in the main coffee producing regions, as happened in previous years.
In Matopiba, a region that includes areas of Maranhão, Tocantins, Piauí and Bahia, the forecast for below-average rain could reduce water levels in the soil, damaging planting and the initial phases of second-crop crops. “There shouldn’t be many impacts because this period is not one of great agricultural production. In some places, this rainfall being below average is even beneficial when it comes to harvesting and transporting the crop in these regions”, says the meteorologist.